In January 2019 the UK introduced 18th Edition wiring regulations (722.531.2.101) for EVSE installations that requires the use of either a Type B RCD (with built in dc capability/detection) or “RCD Type A and appropriate equipment that provides disconnection of the power supply in case of DC fault current above 6mA”.

Since the EmonEVSE / OpenEVSE does not have DC detection this type B RCD is required for installation.